Surface protection composition and terminal fitted electric wire

ABSTRACT

A surface protection composition stably protecting a metal surface even at a high temperature, and a terminal-fitted electric wire improved in anticorrosion property by using the composition. The surface protection composition contains a high-consistency material (A) containing a lubricant base oil and an amide compound, and a composition (B) containing a phosphorus compound containing one or more compounds represented by the general formulae (1) and (2) and a metal. The mass ratio (A):(B) of the high-consistency material (A) to the composition (B) is within a range of 50:50 to 98:2. The lubricant base oil has a kinematic viscosity of 10 mm 2 /s or higher at 100° C. and a number-average molecular weight of 400 or higher:

TECHNICAL FIELD

The present invention relates to a surface protection composition and a terminal fitted electric wire and, more specifically, to a surface protection composition excellent in an anticorrosion property for preventing metal corrosion, and a terminal fitted electric wire excellent in an anticorrosion property treated with the surface protection composition.

BACKGROUND ART

For metal equipment and metal components, grease is used for the purpose of lubrication and corrosion resistance. For example, Patent Literature 1 describes the use of grease containing a perfluoroether base oil, a consistency improver, barium sulfate, or antimony oxide to machinery parts. Patent Literature 2 proposes the use of a surface treatment agent containing 30 to 95 mass % of a volatile liquid having a boiling point of 300° C. or lower, 1 to 50 mass % of a lubricant oil and/or an anticorrosive agent, and 0.1 to 50 mass % of a compound containing an amide group.

CITATION LIST Patent Literature

PTL1: JP 4811408 B

PTL2: WO 2009/022629 A

SUMMARY OF INVENTION Problems to be Solved by the Invention

The grease disclosed in Patent Literature 1 shows poor adhesion to the metal. Especially, under the high temperature conditions, the grease is likely to leak from the metal surface, and thus difficulty arises in protecting the metal surface stably. This is presumably because the grease of Patent Literature 1 is not chemically bonded to the metal surface, but it merely adheres to the metal surface through Van der Waals force, which provides weaker adsorption. The surface treatment agent in Patent Literature 2 also shows poor adhesion to a metal. Especially, under high temperature environments, the surface treatment agent is likely to leak from the metal surface, and thus is hard to protect the metal surface stably.

It is an object of the present invention to provide a surface protection composition stably protecting a metal surface even at a high temperature, and a terminal-fitted electric wire using the composition.

Solution to Problem

In order to solve the foregoing problem, the surface protection composition according to the present invention contains a high-consistency material (A) containing a lubricant base oil and an amide compound; and a composition (B) containing a phosphorus compound containing one or more selected from compounds represented by the general formulae (1) and (2) and a metal, wherein a mass ratio (A):(B) of the high-consistency material (A) to the composition (B) is within a range of 50:50 to 98:2, and the lubricant base oil has a kinematic viscosity of 10 mm²/s or higher at 100° C. and a number-average molecular weight of 400 or higher:

where X¹ to X⁷ each represent independently an oxygen atom or a sulfur atom, R¹¹ to R¹³ each represent independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, among which at least one is a hydrocarbon group having 1 to 30 carbon atoms, and R¹⁴ to R¹⁶ each represent independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atom among which at least one is a hydrocarbon group having 1 to 30 carbon atoms.

The surface protection composition according to the present invention preferably has a shear viscosity 1000 mPa·s or higher at 100° C.

The amide compound preferably contains one or more compounds represented by the below-presented general formulae (3) to (5):

R²¹—CO—NH—R²²  (3)

R²³—CO—NH—Y³¹—NH—CO—R²⁴  (4)

R²⁵—NH—CO—Y³²—CO—NH—R²⁶  (5),

where R²¹ to R²⁶ each represent independently a saturated or unsaturated linear hydrocarbon group having 5 to 25 carbon atoms, except that R²² may be hydrogen, and Y³¹ and Y³² each represent a divalent hydrocarbon group having 1 to 10 carbon atoms selected from an alkylene group and a phenylene group having 1 to 10 carbon atoms, or an alkylphenylene group having 7 to 10 carbon atoms.

The amide compound is preferably a fatty acid amide having a melting point within a range of 20° C. to 200° C.

The phosphorus compound preferably has one or more branched structures or one or more carbon-carbon double bond structures in the structure of the hydrocarbon groups.

The metal forming the composition together with the phosphorus compound is preferably at least one selected from alkali metals, alkaline earth metals, aluminum, titanium, and zinc.

The composition of the phosphorus compound and the metal preferably has a molecular weight of 3000 or lower. The surface protection composition according to the present invention is preferably used for anticorrosion purpose by close contact with the surface of a metal component to be protected so as to cover the surface, thereby preventing metal corrosion.

The terminal-fitted electric wire according to the present invention is a wire in which an electric connection part between a terminal and an electric conductor is covered with the surface protection composition.

Advantageous Effects of Invention

The surface protection composition according to the present invention contains the high-consistency material (A) containing the lubricant base oil and the amide compound, the composition (B) containing the phosphorus compound containing one or more selected from compounds represented by the above general formulae (1) and (2) and the metal. Further, the mass ratio (A):(B) is within a range of 50:50 to 98:2. The kinematic viscosity of the lubricant base oil is 10 mm²/s or higher at 100° C. and the number-average molecular weight of the lubricant base oil is 400 or higher. Containing the ingredients, the surface protection composition is hard to suffer the oxidative degradation even at a high temperature and maintains high viscosty, whereby outward flow of the composition is suppressed even at a high temperature. Thus, the surface protection composition can stably protects a metal surface even at a high temperature.

When the surface protection composition according to the present invention has the shear viscosity of 1000 mPa·s or higher at 100° C., outward flow of the composition tends to be suppressed even at a high temperature.

When the phosphorus compound in the surface protection composition according to the present invention has one or more branched structures or one or more carbon-carbon double bond structures in the structure of the hydrocarbon group, which contributes to improvement in compatibility of the phosphorus compound with the lubricant base oil.

Further, when the metal forming the composition together with the phosphorus compound is at least one member selected from alkali metals, alkaline earth metals, aluminum, titanium, and zinc, the adhesion of the surface protection composition when applied to a metal surface is improved.

When the composition of the phosphorus compound and the metal has a molecular weight of 3000 or lower, the compatibility of the composition of the phosphorus compound and the metal with the lubricant base oil is improved.

Further, in the terminal-fitted electric wire according to the present invention, an electric connection part between a terminal and a wire conductor is covered with the surface protection composition. Therefore, a metal surface such as of the terminal and the wire conductor is stably protected even at a high temperature with a high anticorrosion property of the terminal-fitted electric wire maintained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a terminal-fitted electric wire according to a preferred embodiment of the present invention.

FIG. 2 is a longitudinal cross sectional view along line A-A in FIG. 1.

DESCRIPTION OF EMBODIMENTS

Next, a preferred embodiment of the present invention is to be described specifically.

The surface protection composition according to the present invention (hereinafter sometimes referred to as the present surface protection composition) contains a high-consistency material (A) containing a lubricant base oil and an amide compound; a composition (B) containing a specific phosphorus compound and a metal.

The lubricant base oil used herein includes any one of a mineral oil, a wax isomerized oil, and a synthetic oil, which are usually used as a mixture of two or more of them. Specific examples of the mineral oil used herein include paraffinic and naphthenic oils, and n-paraffin, which are purified from lubricant oil fractions obtained by distillation under ordinary pressure or distillation under reduced pressure of crude oils by appropriately combining purification treatments such as solvent deasphaltation, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid cleaning, and white clay treatment of a lubricant oil fractions.

The wax isomerized oils used herein include those prepared through a hydrogen isomerization treatment of a wax raw material, such as natural wax, e.g., petroleum slack wax obtained through solvent dewaxing of a hydrocarbon oil, or a synthetic wax formed by the so-called Fischer Tropsch synthetic process, in which a mixture of carbon monoxide and hydrogen is brought in contact with a suitable synthetic catalyst at a high temperature and a high pressure. In a case of using the slack wax as the wax raw material, since the slack wax contains large amounts of sulfur and nitrogen, which are unnecessary in the lubricant base oil, it is desirable that the slack wax is hydrogenated as needed to prepare a wax raw material reduced in the sulfur content and the nitrogen content.

Examples of the synthetic oil are not particularly limited, and include a poly-α-olefin, such as a 1-octene oligomer, 1-decene oligomer, and ethylene-propylene oligomer or a hydrogenated product thereof, isobutene oligomer and hydrogenated products thereof, isoparaffin, alkylbenzene, alkylnaphthalene, diester (for example, ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate), polyol ester (for example, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate), polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether, etc.

The lubricant base oil is used which has a kinematic viscosity of 10 mm²/s or higher at 100° C. and the number-average molecular weight of 400 or higher. As the kinematic viscosity of the lubricant base oil increases, the kinematic viscosity of the present surface protection composition increases, whereby the outward flow of the composition tends to be suppressed even at a high temperature. Further, from this viewpoint, the kinematic viscosity is more preferably 15 mm²/s or higher, further more preferably 20 mm²/s or higher. Still further, in view of ease of application on a surface, the kinematic viscosity is more preferably 150 mm²/s or lower, further more preferably 120 mm²/s or lower. The kinematic viscosity is more preferably within a range of 2 to 130 mm²/S at 100° C. because the volatility and the handleability in production are excellent. The kinematic viscosity is measured according to JIS K 2283.

The lubricant base oil has a number-average molecular weight of 400 or higher. Thus, the molecular weight is sufficiently high to suppress oxidative degradation of the oil under high temperature environments, whereby the reduction of the viscosity is suppressed. Since the kinematic viscosity of the lubricant base oil is kept high in a high temperature environment, the outward flow of the composition is suppressed even at a high temperature. Further, from this viewpoint, the number-average molecular weight is more preferably 450 or higher. Still further, in view of ease of application on a surface, the number-average molecular weight is more preferably 10000 or lower, further more preferably 8000 or lower.

The amide compound forms a network structure by hydrogen bonds in the lubricant base oil. This provides the lubricant base oil with the consistency to be a grease-like high-consistency material. That is, when it is used together with the lubricant base oil, a gel-like product is formed at a normal temperature. That is, the amide compound forms a gel (i.e., a semi-solid) of the liquid lubricant base oil at a normal temperature. The high-consistency material is maintained due to its consistency on the coat surface of the material to be coated at a normal or high temperature.

The amide compound is a compound having one or more amide groups (—NH—CO—), and a mono-amide compound having one amide group or a bis-amide compound having two amide groups can be used preferably.

Compounds, for example, represented by the below-presented general formulae (3) to (5) can be used as the amide compound. They may be used alone or two or more of them may be used in combination.

R²¹—CO—NH—R²²  (3)

R²³—CO—NH—Y³¹—NH—CO—R²⁴  (4)

R²⁵—NH—CO—Y³²—CO—NH—R²⁶  (5)

In the general formulae (3) to (5), R²¹ to R²⁶ each represent independently a saturated or unsaturated linear hydrocarbon group having 5 to 25 carbon atoms, provided that R²² may be hydrogen; and Y³² and Y³² each represent a divalent hydrocarbon group having 1 to 10 carbon atoms selected from an alkylene group or a phenylene group having 1 to 10 carbon atoms, and an alkylphenylene group having 7 to 10 carbon atoms. Further, in the general formulae (3) to (5), hydrogen atoms of the hydrocarbon group constituting R²¹ to R²⁶ may be partially substituted by a hydroxyl group (—OH).

The amide compound represented by the general formula (3) includes, specifically, a saturated fatty acid amide such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide, an unsaturated fatty acid amide such as oleic acid amide and erucic acid amide, and a substituted amide of a saturated or unsaturated long-chain fatty acid and a long-chain amine such as stearylstearic acid amide, oleyloleic acid amide, oleylstearic acid amide, and stearyloleic acid amide. Among them, an amide compound in which at least one of R²¹ to R²² in the general formula (3) is a saturated linear hydrocarbon group having 12 to 20 carbon atoms such as, for example, an amide compound in which R²¹ is a saturated linear hydrocarbon group having 12 to 20 carbon atoms and R²² is a hydrogen atom in the general formula (3), or an amide compound in which each of R²¹ and R²² in the general formula (3) is a saturated linear hydrocarbon group having 12 to 20 carbon atoms is preferred. More specifically, stearylstearic acid amide is preferred.

The amide compound represented by the general formula (4) includes, specifically, ethylenebis-stearic acid amide, ethylene bis-isostearic acid amide, ethylene bis-oleic acid amide, methylene bis-lauric acid amide, hexamethylene bis-oleic acid amide, hexamethylene bis-hydroxystearic acid amide, and m-xylylene bis-stearic acid amide. Among them, an amide compound in which at least one of R²³ and R²⁴ in the general formula (4) is a saturated linear hydrocarbon group having 12 to 20 carbon atoms, for example, an amide compound in which R²³ is a saturated linear hydrocarbon group having 12 to 20 carbon atoms and R²⁴ is a hydrogen atom in the general formula (4), or an amide compound in which each of R²³ and R²⁴ is a saturated linear hydrocarbon group having 12 to 20 carbon atoms in the general formula (4) is preferred. More specifically, ethylene bis-isostearic acid amide is preferred.

A specific example of the amide compound represented by the general formula (5) includes N,N′-distearyl sebacic acid amide. Among them, an amide compound in which at least one of R²⁵ and R²⁶ in the general formula (5) is a saturated linear hydrocarbon group having 12 to 20 carbon atoms, for example, an amide compound in which R²⁵ is a saturated linear hydrocarbon group having 12 to 20 carbon atoms and R²⁶ is a hydrogen atom in the general formula (5) or an amide compound in which each of R²⁵ and R²⁶ in the general formula (5) is a saturated linear hydrocarbon group having 12 to 20 carbon atoms is preferred.

From a viewpoint of keeping a gel state (semi-solid state) at a normal temperature when mixed with a lubricant base oil or keeping a gel-state (semi-solid state) alone at a normal temperature, the amide compound preferably has a melting point of 20° C. or higher. The melting point is more preferably 50° C. or higher, even more preferably 80° C. or higher, and particularly preferably 120° C. or higher. Further, the melting point is preferably 200° C. or lower, more preferably 180° C. or lower, even more preferably 150° C. or lower. Further, the molecular weight of the amide compound is preferably within a range of 100 to 1000, and more preferably within a range of 150 to 800.

From a viewpoint of keeping the gel-state (semi-solid state) at a normal temperature when mixed with the lubricant base oil and keeping a gel state (semi-solid state) alone at a normal temperature, the content of the amide compound is preferably 1 mass part or higher with respect to 100 mass parts of the lubricant base oil. The content is more preferably 2 mass parts or higher, and even more preferably 5 mass parts or higher. Further, the content is preferably 70 mass parts or lower, more preferably 60 mass parts or lower, and even more preferably 50 mass parts or lower with respect to 100 mass parts of the lubricant base oil. Preferably, the content is 60 mass parts or lower, and more preferably 50 mass parts or lower.

A specific phosphorus compound contains one or more compounds represented by the below-presented general formulae (1) and (2):

where X¹ to X⁷ each represent independently an oxygen atom or a sulfur atom, R¹¹ to R¹³ each represent independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms and at least one of them is a hydrocarbon group having 1 to 30 carbon atoms, R¹⁴ to R¹⁶ each represent independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms and at least one of them is a hydrocarbon group having 1 to 30 carbon atoms.

Examples of the hydrocarbon group include alkyl group, cycloalkyl group, alkyl-substituted cycloalkyl group, alkenyl group, aryl group, alkyl-substituted aryl group, and aryl alkyl group.

Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyal group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, and octadecyl group. They may be either linear or branched.

Examples of the cycloalkyl group include cyclopentyl group, cyclohexyl group, and cycloheptyl group. Examples of the alkyl-substituted cycloalkyl group include methylcyclopentyl group, dimethylcyclopentyl group, methylethylcyclopentyl group, diethylcyclopentyl group, methylcyclohexyl group, diethylcyclohexyl group, methylethylcyclohexyl group, diethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group, methylethylcyclopeptyl group, and diethylcycloheptyl group. The substitution position of the alkyl-substituted cycloalkyl group is not particularly restricted. The alkyl group may be linear or branched.

Examples of the alkenyl group include butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, and octadecenyl group. They may be either linear or branched.

Examples of the aryl group include phenyl group, and naphthyl group. Example of Alkyl-substituted aryl group include tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group and dodecylphenyl group. The substitution position of the alkyl substituted aryl group is not particularly restricted. The alkyl group may be linear or branched. Examples of the arylalkyl group include benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpengyl group, and phenylhexyl group. The alkyl group may be linear or branched.

All of X¹ to X⁷ are preferably oxygen atoms. The hydrocarbon groups R¹¹ to R¹⁶ having 1 to 30 carbon atoms are preferably hydrocarbon groups having 4 to 30 carbon atoms, and more preferably hydrocarbon groups having 8 to 30 carbon atoms.

Preferably, at least one of R¹¹ to R¹³ is a hydrogen group and at least another one of them is a hydrocarbon atom having 1 to 30 carbon atoms. Preferably, at least one of R¹⁴ to R¹⁶ is a hydrogen atom and at least another one of them is a hydrocarbon group having 1 to 30 carbon atoms.

Examples of the phosphorus compound represented by the general formula (1) include phosphorous acid, monothiophosphorous acid, dithiophosphorous acid, phosphite monoester, monothiophosphite monoester, dithiophosphite monoester, phosphite diester, monothiophosphite diester, dithiophosphite diester, phosphite triester, monothiophosphite triester, and dithiophosphite triester. They may be used alone or two or more of them may be used in combination as the phosphorus compounds represented by the general formula (1).

Examples of the phosphorus compound represented by the general formula (2) include phosphoric acid, monothiophosphoric acid, dithiophosphoric acid, phosphate monoester, monothiophosphate monoester, dithiophosphate monoester, phosphate diester, monothiophosphate diester, dithiophosphate diester, phosphate triester, monothiophosphate triester, and dithiophosphate triester. They may be used alone or two or more of them may be used in combination as the phosphorus compound represented by the general formula (2).

For the phosphorus compound, from a viewpoint of compatibility improving effect with the high-consistency material (A), stickiness improving effect, adhesion improving effect to a metal surface to be protected, etc., the phosphorus compound represented by the general formula (2) is more preferred. Further, among the phosphorus compounds represented by the general formula (2), acidic phosphate ester represented by the below-presented general formula (6) or general formula (7) is particularly preferred.

P(═O)(—OP¹⁴)(—OH)₂  (6)

P(═O)(—OP¹⁴)₂(—OH)  (7)

Examples of the metal that forms the composition together with the specific phosphorus compound include an alkali metal such as Li, Na, and K, an alkaline earth metal such as Mg and Ca, aluminum, titanium, zinc, etc. They may be used alone or two or more of them may be used in combination. The metals can provide good adsorption to the metal surface due to their relatively high ionization tendency. Further, since the ionization tendency is, for example, higher than that of Sn, it can be excellent in the ion bondability to Sn. Among them, Ca and Mg are more preferred from a viewpoint for example, of waterproofness. The metal forming the composition with the specific phosphorus compound preferably has a valence of two or more from a viewpoint of increase of the molecular weight of the composition and heat resistance.

The metal source for the composition containing the specific phosphorus compound and the metal includes a metal hydroxide, a metal carboxylate, etc. The carboxylic acid of the metal carboxylate includes salicylic acid, benzoic acid, phthalic acid, etc. The metal salt of the carboxylic acid is a neutral salt. The metal salt may be a basic salt, or may be a hyper basic salt. Among them, hyper basic salicylic acid or the like is preferred from a viewpoint of the solubility and reactivity of metal ions during reaction.

In the composition of the specific phosphorus compound and the metal, when at least one of the hydrocarbon group of the specific phosphorus compound is a hydrocarbon group having 4 to 30 carbon atoms, the compatibility of the composition of the specific phosphorus compound and the metal with the lubricant base oil, which is the long-chained alkyl compound, is improved. The hydrocarbon group is an organic group containing carbon and hydrogen but not containing heteroelements such as N, O, and S. Then, in view of the compatibility of the composition of the specific phosphorus compound and the metal with the lubricant base oil, which is the long-chained alkyl compound, the hydrocarbon group of the specific phosphorus compound is preferably an aliphatic hydrocarbon group or a cycloaliphatic hydrocarbon group. More preferably, it is an aliphatic hydrocarbon group.

The aliphatic hydrocarbon group may be an alkyl group consisting of a saturated hydrocarbon or an alkenyl group consisting of an unsaturated hydrocarbon. The alkyl group or the alkenyl group as the aliphatic hydrocarbon group may be either linear or branched. However, when the alkyl group is a linear alkyl group such as an n-butyl group or n-octyl group, alkyl chains tend to be aligned to each other and increase the crystallinity of the composition of the specific phosphorus compound and the metal, lowering the solubility with the lubricant base oil. In view of the above, when the hydrocarbon group is an alkyl group, a branched alkyl group is more preferred compared to a linear alkyl group. On the other hand, since the alkenyl group has one or more carbon-carbon double bonds, it has not so-high crystallinity even if it has a linear structure. Accordingly, the alkenyl group may either be linear or branched.

When the number of carbon atoms of at least one hydrocarbon group is lower than 4, the specific phosphorus compound becomes inorganic. Further, the specific phosphorus compound tends to increase the crystallinity. Then, it shows poor solubility with the lubricant base oil and is no longer compatible with the lubricant base oil. On the other hand, if the number of carbon atoms of the hydrocarbon group is more than 30, the specific phosphorus compound shows excessively high viscosity and tends to lower the fluidity. The number of carbon atoms of the hydrocarbon group is preferably 5 or more and, more preferably, 6 or more in view of the compatibility of the hydrocarbon group with the lubricant base oil. Further, the number of carbon atoms of the hydrocarbon group is preferably 26 or lower and, more preferably, 22 or lower from a viewpoint of fluidity, etc.

Further, the composition of the specific phosphorus compound and the metal has a phosphate group (polar group) and a non-polar group (hydrocarbon group in the ester moiety) together in the molecule, and can be present in a layered state in which polar groups are associated to each other and non-polar groups are associated to each other and, accordingly, the composition can be a highly viscous liquid even in a non-polymerized state. If it is a viscous liquid, the composition can be adhered more strongly to the metal surface through physical adsorption due to Van der Waals force. The viscosity is presumably obtained by the entanglement caused between linear molecular chains to each other. In view of the above, it is preferred that the specific phosphorus compound is designed not to promote crystallization. Specifically, for this purpose, the hydrocarbon groups each have a number of carbon atoms from 4 to 30, has one or more branched chain structures or one or more carbon-carbon double bonds, etc.

From a viewpoint of the adhesion, it is necessary that the specific phosphorus compound forms a composition together with the metal. When the specific phosphorus compound itself which is not composited with the metal is used, the polarity of the phosphate group portion is small, the association (cohesion property) between the polar phosphate groups is low, and a liquid of high viscosity is not formed. Accordingly, adhesion (viscosity) is low. Further, when the specific phosphorus compound is composited with ammonia or an amine, the polarity at a portion of the phosphate group is small, and the association (cohesion property) between the phosphate groups, which are polar groups, to each other is low, failing to form a liquid at high viscosity. Accordingly, the adhesion (viscosity) is low.

More specific examples of the hydrocarbon group include oleyl group, stearyl group, isostearyl group, 2-ethylhexyl group, butyloctyl group, isomyristyl group, isocetyl group, hexyldecyl group, octyldecyl group, octyldodecyl group, and isobehenyl group.

Further, specific examples of the acid phosphate ester include butyloctyl acid phosphate, isomyristyl acid phosphate, isocetyl acid phosphate, hexyldecyl acid phosphate, isostearyl acid phosphate, isobehenyl acid phosphate, octyldecyl acid phosphate, octyldodecyl acid phosphate, isobutyl acid phosphate, 2-ethylhexyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate, stearyl acid phosphate, oleyl acid phosphate, myristyl acid phosphate, palmityl acid phosphate, di-butyloctyl acid phosphate, di-isomyristyl acid phosphate, di-isocetyl acid phosphate, di-hexyldecyl acid phosphate, di-isostearyl acid phosphate, di-isobehenyl acid phosphate, di-octyldecyl acid phosphate, di-octyldodecyl acid phosphate, di-isobutyl acid phosphate, di-2-ethylhexyl acid phosphate, di-isodecyl acid phosphate, di-tridecyl acid phosphate, di-oleyl acid phosphate, di-myristyl acid phosphate, di-palmityl acid phosphate, etc. Among them, from a viewpoint, for example, of non-crystallinity and molecular chain entanglement with the lubricant base oil, oleyl acid phosphate and isostearyl acid phosphate are preferred.

The molecular weight of the composition of the specific phosphorus compound and the metal is preferably 3,000 or lower because the compatibility of the composition of the specific phosphorus compound and the metal with the high-consistency material is improved by fine dispersion. The molecular weight is more preferably 2,500 or lower. Further, the molecular weight is preferably 80 or higher, and more preferably 100 or higher from a viewpoint, for example, of inhibiting separation due to increased concentration of the polar group. The molecular weight can be evaluated by calculation.

To the present surface protection composition, an organic solvent, a stabilizer, a corrosion inhibitor, a dye, a viscosity improver, a filler, etc. can be added in addition to the high-consistency material (A), and the composition (B) as long as the function of the present surface protection composition is not deteriorated.

In the present surface protection composition, the mass ratio (A):(B) of the high-consistency material (A) to the composition (B) is within a range of 50:50 to 98:2. Thus, the present surface protection composition is excellent in adhesion to a metal, refrains from leaking from a metal surface under the high temperature conditions, and stably protects the metal surface. Further, the surface protection composition forms a film having a sufficient thickness to exhibit an excellent anticorrosion property.

In the present surface protection composition, the mass ratio (A):(B) of the high-consistency material (A) to the composition (B) is preferably within a range of 60:40 to 95:5, and more preferably within a range of 70:30 to 90:10 from the viewpoint of having a sufficient film thickness and sufficient adhesion to a metal.

The surface protection composition according to the present invention preferably has a shear viscosity of 1000 mPa·s or higher at 100° C. Then, the composition tends to be suppressed outward flow even at a high temperature. In addition, from this viewpoint, the shear viscosity is more preferably 1100 mPa·s or higher, further more preferably 1200 mPa·s or higher. Meanwhile, from the viewpoint of ease of application on a surface, the shear viscosity is more preferably 2500 mPa·s or lower, more preferably 2000 mPa·s or lower. The shear viscosity is measured according to JIS K7117-2 under conditions of a temperature of 100° C. and a shear rate of 100/s. The viscosity can be measured with a cone-plate rotational viscometer. The shear viscosity may be adjusted depending on the kinematic viscosity of the lubricant base oil, the contents of the high-consistency material (A) and the composition (B), and the content of the amide compound, etc.

The softening point of the present surface protection composition is preferably 150° C. or lower, which suppress the materials from being deteriorated due to heat during application. From this viewpoint, the softening point is more preferably 140° C. or lower, further more preferably 130° C. or lower. On the other hand, from the viewpoint of maintaining a high anticorrosion property, the softening point of the present surface protection composition is preferably 100° C. or higher, more preferably 110° C. or higher, furthermore preferably 120° C. or higher. The softening point of the present surface protection composition may be adjusted depending on the types (melting points) in the amide compound of the high-consistency material (A), the content of the high-consistency material (A), the content of the amide compound, etc.

The present surface protection composition may be obtained by mixing of the high-consistency material (A), the composition (B), and components to be added if needed. Further, the present anticorrosive agent may also be obtained by mixing of the lubricant base oil, the amide compound, the composition (B), and components to be added if needed.

After coating of a surface with the surface protection composition, a high-consistency film is sustained on the coating surface due to the consistency of the high-consistency material. If an amide compound having a higher melting point is used, the consistency may be maintained at a high temperature, which is high but lower than the melting point, in the same way at room temperature, leading to sustainment of the high-consistency film on the coating surface at the high temperature. The composition of the specific phosphorous compound and the metal works as a metal absorption component and contributes to improvement of adhesion of the high-consistency film with the metal surface. Since the lubricant base oil has the kinematic viscosity of 10 mm²/s or higher at 100° C. and the number-average molecular weight of 400 or higher, the oxidative degradation of the oil is suppressed under high temperature environments, whereby reduction of the viscosity is suppressed. Thus, the present surface protection composition is hard to flow outward and stably protects the metal surface even at a high temperature. The present surface protection composition may be applied on the surface of a coating material by spreading the present surface protection composition on the surface of a material to be coated or immersing a coating material into the present surface protection composition.

The thickness of the high-consistency film coated on the surface of the material to be coated is preferably 100 μm or smaller from a viewpoint of preventing outward flow or preventing leakage from the coated portion. The thickness is more preferably 50 μm or smaller. On the other hand, the thickness is preferably at a predetermined thickness or larger from a viewpoint, for example, of mechanical strength, etc. of the high-consistency film to be coated. The lower limit of the film thickness includes, for example, 0.5 μm, 2 μm, 5 μm, etc.

The present surface protection composition can be used for anticorrosion purpose, etc. The present surface protection composition can be used, for example, for an anticorrosion purpose by close contact with the surface of a metal component to be protected so as to cover the surface, thereby preventing metal corrosion. For use in the anticorrosion purpose, it can be used, for example, as an anticorrosive agent for a terminal-fitted electric wire.

Next, a terminal-fitted electric wire according to the present invention is to be described.

A terminal-fitted electric wire according to the present invention is an electric wire in which a terminal is connected to the conductor end of the insulation electric wire, and the electric connection portion between the terminal and the electric wire conductor is covered with a high-consistency film including a high-consistency material containing a lubricant base oil and an amide compound, and a composition of a specific phosphorus compound and a metal of the present surface protection composition. Thus, corrosion at the electric connection portion is prevented.

FIG. 1 is a perspective view of a terminal-fitted electric wire according to a preferred embodiment of the present invention, and FIG. 2 is a vertical cross sectional view along line A-A in FIG. 1. As illustrated in FIG. 1 and FIG. 2, in a terminal-fitted electric wire 1, an electric wire conductor 3 of a covered electric wire 2 covered with an insulation covering (insulator) 4 and a terminal 5 are electrically connected through an electric connection portion 6.

The terminal 5 has a tab-shaped connection part 51 formed by an elongate flat plate to be connected with a mating terminal, and an electric wire fixing portion 54 containing a wire barrel 52 and an insulation barrel 53 formed at the extended end of the connection portion 51. The terminal 5 can be formed (or fabricated) to a predetermined shape by pressing a plate material made of a metal.

In the electric connection portion 6, the insulation covering 4 at the end of the covered electric wire 2 is stripped to expose the electric wire conductor 3, and the exposed electric wire conductor 3 is press-bonded to one side of the terminal 5 to connect the covered electric wire 2 with the terminal 5. The wire barrel 52 of the terminal 5 is crimped over the electric wire conductor 3 of the covered electric wire 2 to electrically connect the electric wire conductor 3 with the terminal 5. Further, the insulation barrel 53 of the terminal 5 is crimped over the insulation covering 4 of the covered electric wire 2.

In the terminal-fitted electric wire 1, an area surrounded by a dotted chain is covered with a high-consistency film 7 obtained from the present surface protection composition. Specifically, an area from the surface portion of the terminal 5 ahead of the front end of the electric wire conductor 3 exposed from the insulation covering 4 to the surface portion of the insulation covering 4 behind the backward end of the electric wire conductor 3 exposed from the insulation covering 4 is covered with the high-consistency film 7. That is, beyond the front end 2 a of the covered electric wire 2, the terminal-fitted electric wire 1 is covered with the high-consistency film 7 in an area that protrudes slightly from the front end of the electric wire conductor 3 to the connection portion 51 of the terminal 5. The front end 5 a of the terminal 5 of the terminal-fitted electric wire 1 is also covered with the high-consistency film 7 in an area that protrude slightly from the end of the insulation barrel 53 to the side of the insulation covering 4 of the covered electric wire 2. Then, as shown in FIG. 2, the lateral side 5 b of the terminal 5 is also covered with the high-consistency film 7. The back surface 5 c of the terminal 5 may or may not be covered with the high-consistency film 7. The peripheral end of the high-consistency film 7 contains a portion in contact with the surface of the terminal 5, a portion in contact with the surface of the electric wire conductor 3, and a portion in contact with the surface of the insulation covering 4.

In this way, the electric connection portion 6 is covered with the high-consistency film 7 at a predetermined thickness along the shape of the outer periphery of the terminal 5 and the covered electric wire 2. Thus, a portion of the electric wire 2 from which the electric wire conductor 3 is exposed is completely covered with the high-consistency film 7 so as not to be exposed to the outside. Accordingly, the electric connection portion 6 is completely covered with the high-consistency film 7. Since the high-consistency film 7 has excellent adhesion to all of the electric wire conductor 3, the insulation covering 4, and the terminal 5, the high-consistency film 7 prevents intrusion of moisture, etc. from the outside to the electric wire conductor 3 and the electric connection portion 6, which may cause corrosion of the metal portions. Further, since the high-consistency film 7 is excellent in adhesion, a gap is less likely to be formed between the high-consistency film 7 and any of the electric wire conductor 3, the insulation covering 4, and the terminal 5 at the peripheral end of the high-consistency film 7 even when the electric wire is bent, for example, in the process from the production of the wire harness to the attachment to a vehicle, thereby maintaining the waterproofness and anticorrosion function.

The present surface protection composition forming the high-consistency film 7 is coated for a predetermined range. For the application of the present surface protection composition forming the high-consistency film 7, known methods such as dripping, coating, etc. can be used.

The high-consistency film 7 is formed at a predetermined thickness in a predetermined area. The thickness is, preferably, within a range of 0.01 to 0.1 mm. If the high-consistency film 7 is excessively thick, it is difficult to insert the terminal 5 into a connector. If the high-consistency film 7 is excessively thin, the anticorrosion function tends to be lowered.

The electric wire conductor 3 of the covered electric wire 2 is a stranded wire composed of a plurality of wires 3 a. In this case, the stranded wire may be composed of a single type of metal wires or two or more types of metal wires. Further, the stranded wire may also be composed of organic fibers in addition to metal wires. The stranded wire composed of a single type of metal wires means that all metal wires forming the stranded wire are formed from the same metal material, while the stranded wire composed of two or more types of metal wires means that the stranded wire contains metal wires formed from different metal materials. The stranded wire may also include reinforcing wires (tension members) for reinforcing the covered electric wire 2.

Examples of the material for metal wire forming the electric wire conductor 3 include copper, copper alloys, aluminum, aluminum alloys, or materials formed by applying various platings to the materials described above. Examples of the material for the metal wire as the reinforcing wires include copper alloys, titanium, tungsten, stainless steels, etc. Further, example of the organic fibers as the reinforcing wire include KEVLAR. Metal wires forming the electric wire conductor 3 are preferably aluminum, aluminum alloys or materials formed by applying various types of plating to the materials described above from a viewpoint of reducing the weight.

Examples of the material for the insulation covering 4 include rubber, polyolefin, PVC, thermoplastic elastomer, etc. They may be used alone or two or more of them may be used in combination. Various additives may be added as required to the material of the insulation covering 4. Examples of the additives include flame retardants, fillers, colorants, etc.

The material for the terminal 5 (material for a substrate) includes various copper alloys, copper, etc. in addition to generally used brass. The surface of the terminal 5 may be applied with plating of various metals such as tin, nickel, and gold partially (for example, to contacts) or entirely.

While a terminal is press-bonded to the end of the electric wire conductor in the terminal-fitted electric wire 1 illustrated in FIG. 1, other known electric connection methods such as welding may also be used instead of the press-bonding connection.

EXAMPLE

The present invention is to be described by way of examples but the present invention is not restricted to the examples.

(Preparation of High-Consistency Material)

High-consistency materials were prepared by mixing lubricant base oils and amide compounds according to content ratio (parts by mass) shown in Table 1.

Lubricant base oil A: Mineral type base oil (number-average molecular weight Mn=500, kinematic viscosity=4.0 mm²/s (100° C.)).

Lubricant base oil B: Mineral type base oil (number-average molecular weight Mn=400, kinematic viscosity=11.1 mm²/s (100° C.)).

Lubricant base oil C: Synthetic type base oil (number-average molecular weight Mn=1000, kinematic viscosity=50.0 mm²/s (100° C.)).

Lubricant base oil D: Synthetic type base oil (number-average molecular weight Mn=7000, kinematic viscosity=100.0 mm²/s (100° C.)).

Lubricant base oil E: Synthetic type base oil (number-average molecular weight Mn=350, kinematic viscosity=8.0 mm²/s (100° C.)).

Amide compound: Ethylene bis-stearylamide “SLIPACKS E” (melting point 150° C., molecular weight 592) manufactured by Nippon Kasei Chemical Co. Ltd.

(Preparation of Composition of Phosphorus Compound and Metal)

<Preparation Example 1> OL-Ca

Into a 500 mL flask, 50 g (acid value: 0.163 mol) of oleyl acid phosphate (“Phoslex A18D” manufactured by SC Organic Chemical Co., Ltd., molecular weight: 467 (average), acid value: 183 mg KOH/g) and 50 mL of methanol were put into and stirred at room temperature to form a uniform solution. Into the solution, 6.04 g (0.0815 mol) of calcium hydroxide was added. The suspension was stirred for 24 hours at room temperature, and filtered after confirming that there was no calcium hydroxide precipitates. Then, methanol and generated water were distilled off under a reduced pressure by a rotary evaporator. Then, after adding 50 mL of toluene, the generated water was distilled off by azeotropy through vacuum distillation to obtain a clear and high-consistency aimed product.

(Preparation of Surface Protection Composition)

Surface protection composition was prepared by mixing the high-consistency material, and the composition of the phosphorus compound and the metal (phosphorus based composition) at the content ratios (mass parts) shown in table 1 while heated at 160° C.

(Measurement of Shear Viscosity)

Viscosity of the surface protection composition was measured according to JIS K7117-2 at 100° C. and a shear rate of 100/s with a cone-plate rotational viscometer.

(Observation of Appearance after High-Temperature Test)

The surface protection composition heated to 160° C. to be liquefied was applied onto an electric connection part between a terminal made of copper and an aluminum conductor of a terminal-fitted electric wire to cover the electric connection part, as illustrated in FIG. 1. Then, the electric connection part was left for 168 hours in a thermostatic chamber held at 100° C. Appearance observation was carried out before and after the high-temperature test, respectively, and if no change was found in appearance after the high-temperature test, the surface protection composition was evaluated as “good”, while if the surface protection composition flowed outward from the terminal, or if the high-consistency film was deformed by heat, the surface protection composition was evaluated as “bad”.

(Corrosion Resistance Performance Test after High-Temperature Test)

The surface protection composition heated to 160° C. to be liquefied was applied onto an electric connection part between a terminal made of copper and an aluminum conductor of a terminal-fitted electric wire to cover the electric connection part, as illustrated in FIG. 1. Then, the terminal-fitted electric wire was left for 168 hours in a thermostatic chamber held at 100° C. Then, a salt spray test was conducted at 35° C. (concentration of solution of salt: 50 g/L) according to JIS C0024 to evaluate generation of rust after 120 hours had passed from starting of the salt spraying. If rust was found through visual inspection even at a single sample among 10 samples (N=10), the surface protection composition was regarded as “poor” in anticorrosion property. If rust was not found through visual inspection at any samples, the surface protection composition was evaluated as “good” in anticorrosion property.

TABLE 1 Number-average Kinematic Examples Comparative Examples molecular weight viscosity (mm²/s) 1 2 3 4 5 6 7 8 9 1 2 3 4 Lubricant 500 32.0 68 34 86 75 38 56 87 33 100 base oil A Lubricant 400 11.1 68 34 base oil B Lubricant 1000 50.0 68 base oil C Lubricant 7000 100.0 68 base oil D Lubricant 350 8.0 68 base oil E Amide compound 12 12 12 12 12 12 5 12 24 12 12 12 Phosphorus compound 20 20 20 20 20 2 20 50 20 1 55 20 shear viscosity (mPa · s) 1400 1300 1600 1900 1350 1200 1100 1050 1650 1100 900 700 — Observation of appearance good good good good good good good good good good bad bad bad (outward flow or deformation at high temperature) Corrosion resistance performance test good good good good good good good good good bad bad bad bad

Based on the test results of examples 1-4 and comparative example 3, it is found that, when the lubricant base oil has a kinematic viscosity of 10 mm²/s or higher at 100° C. and a number-average molecular weight of 400 or higher, the outward flow of the composition is suppressed even at a high temperature, and a high anticorrosion property is maintained even at a high temperature. Further, based on the test results of examples 1, 6, 8, and comparative examples 1 and 2, it is found that, when the mass ratio (A):(B) of the high-consistency material (A) containing the lubricant base oil and the amid compound to the composition (B) containing the phosphorus compound is within the above-described specific range, the outward flow of the composition is suppressed even at a high temperature and the high anticorrosion property is maintained even at a high temperature.

As for comparative example 1, a sufficient anticorrosion property is not obtained since the content of the composition (B) containing the phosphorus compound is small, and thus the adhesion to a metal is poor. As for comparative example 2, outward flow of the composition is caused at a high temperature since the content of the high-consistency material (A) is small. Thus, a sufficient anticorrosion property is not obtained. As for comparative example 3, outward flow of the composition is caused at a high temperature since the lubricant base oil has low viscosity and low number-average molecular weight. Thus, a sufficient anticorrosion property is not obtained. As for comparative example 4, a sufficient anticorrosion property is not obtained since neither the composition (B) containing the phosphorus compound nor the amide compound are contained, and thus the adhesion to the metal is poor. In addition, outward flow of the composition is caused at a high temperature. Thus, a sufficient anticorrosion property is not obtained.

The embodiment of the present invention has been described specifically but the present invention is no way restricted to the embodiment described above but can be modified variously within a range not departing from the gist of the present invention. 

1. A surface protection composition comprising: a high-consistency material (A) comprising: a lubricant base oil; and an amide compound; and a composition (B) containing: a phosphorus compound comprising: one or more selected from compounds represented by the general formulae (1) and (2); and a metal, a mass ratio (A):(B) of the high-consistency material (A) to the composition (B) being within a range of 50:50 to 98:2, the lubricant base oil having a kinematic viscosity within a range of 100 to 150 mm²/s at 100° C. and the number-average molecular weight of 400 or higher:

where X¹ to X⁷ each represent independently an oxygen atom or a sulfur atom, R¹¹ to R¹³ each represent independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, among which at least one is a hydrocarbon group having 1 to 30 carbon atoms, and R¹⁴ to R¹⁶ each represent independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atom among which at least one is a hydrocarbon group having 1 to 30 carbon atoms.
 2. The surface protection composition according to claim 1, wherein the average-molecular weight of the lubricant base oil is within a range of 7000 to
 10000. 3. The surface protection composition according to claim 1, wherein the composition has a shear viscosity of 1000 mPa·s or higher at 100° C.
 4. The surface protection composition according to claim 1, wherein the amide compound comprises one or more selected from compounds represented by the below-presented general formulae (3) to (5): R²¹—CO—NH—R²²  (3) R²³—CO—NH—Y³¹—NH—CO—R²⁴  (4) R²⁵—NH—CO—Y³²—CO—NH—R²⁶  (5), where R²¹ to R²⁶ each represent independently a saturated or unsaturated linear hydrocarbon group having 5 to 25 carbon atoms, except that R²² may be hydrogen, and Y³¹ and Y³² each represent a divalent hydrocarbon group having 1 to 10 carbon atoms selected from an alkylene group and a phenylene group having 1 to 10 carbon atoms, or an alkylphenylene group having 7 to 10 carbon atoms.
 5. The surface protection composition according to claim 1, wherein the amide compound is a fatty acid amide having a melting point within a range of 20° C. to 200° C.
 6. The surface protection composition according to claim 1, wherein the phosphorus compound has one or more branched structures or one or more carbon-carbon double bond structures in the structure of the hydrocarbon groups.
 7. The surface protection composition according to claim 1, wherein the metal forming the composition together with the phosphorus compound is at least one selected from alkali metals, alkaline earth metals, aluminum, titanium, and zinc.
 8. The surface protection composition according to claim 1, wherein the composition of the phosphorus compound and the metal has a molecular weight of 3000 or lower.
 9. The surface protection composition according to claim 1, wherein the composition covers a surface of a metal component with closely contacting the surface, preventing corrosion of the metal component.
 10. A terminal-fitted electric wire, wherein an electric connection part between a terminal and an electric conductor is covered with the surface protection composition according to claim
 1. 